The present invention relates to a sound volume adjusting apparatus which adjusts sound volume in accordance with a received volume setting value.
A slider or a rotary knob is used as an interface for adjusting the sound volume. A slider and a rotary knob can adjust the sound volume in a wide range for a short time period.
However, there is a case where the sound volume is erroneously changed to an unintended high level.
Therefore, JP-A-2002-84589 discloses a related art in which an upper limit of a volume setting value is set, and JP-A-2002-335137 discloses a related art in which sound volume is caused to be slowly changed.
When an upper limit of a volume setting value is set, however, a situation where the sound volume cannot be adjusted to a level which is desired by the user is caused. In a laboratory or the like, for example, there arises no problem even when a sound is reproduced at a high volume level. However, when an upper limit of the volume setting value is set, it is impossible to adjust the sound volume to a high volume level which is actually desired by the user. When the sound volume is slowly changed, the actual change of the volume setting value cannot follow a user's operation of sound volume adjustment, thereby causing a sense of strangeness.